Quoting Harry Elsden
could you please give me some advice as to how to make something like that

The biggest part is having the pieces. Inspiration follows the pieces you have. For the trench, I started building the raised area, then built the trench behind that. The building was simple. As for the cannon, look at reference pictures.

I like the use of netting for camouflage, as well as the purist weapons (an ad for BrickMania custom weapons is on the screen as I write. Coincidence?) However, the house would probably look better if the edges were more uneven and the fallen wall pieces were connected in some way. Overall, nice job!

cool battle scene, you re getting pretty good in greenery too, I d love you d make a GF attack, could you reproduce gf soldiers? it s toy story soldiers with the lego basic face for clones, a ref can be found in cybercity story episodes. great job mike!